6.5

CVE-2026-4426: libarchive Incorrect Bitwise Shift of Integer

CVSS: 6.5v3.1MediumModified
AliasesUBUNTU-CVE-2026-4426DEBIAN-CVE-2026-4426CGA-4mc5-4x7p-96rf
Published 19-03-2026Last modified 01-09-2026
Open JSON

Vulnerability summary

CVE-2026-4426 is a medium (CVSS 6.5) Incorrect Bitwise Shift of Integer vulnerability in libarchive. EPSS estimates a 0.58% chance of exploitation in the next 30 days, higher than 46.6% of scored vulnerabilities.

Overall risk
26/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.58%
0%100%
Low · +0.28 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 9 · Related 7
MGASA-2026-0241MGASA-2026-0366RHSA-2026:8944SUSE-SU-2026:22241-1SUSE-SU-2026:22248-1SUSE-SU-2026:2490-1

Timeline

  1. 19-03-2026
    PublishedVulnerability first disclosed.
  2. 01-09-2026
    Last modifiedVulnerability information updated.

Description

A flaw was found in libarchive. An Undefined Behavior vulnerability exists in the zisofs decompression logic, caused by improper validation of a field (`pz_log2_bs`) read from ISO9660 Rock Ridge extensions. A remote attacker can exploit this by supplying a specially crafted ISO file. This can lead to incorrect memory allocation and potential application crashes, resulting in a denial-of-service (DoS) condition.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.58%

Chance of exploitation in the next 30 days

Percentile

47%

Versus all other CVEs

30-day change

+0.28 pp

From 0.30% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.58%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard4 products
  • libarchive< 3.8.7-r2
  • libarchive-dev< 3.8.7-r2
  • libarchive-doc< 3.8.7-r2
  • libarchive-tools< 3.8.7-r2
Wolfi4 products
  • libarchive< 3.8.7-r2
  • libarchive-dev< 3.8.7-r2
  • libarchive-doc< 3.8.7-r2
  • libarchive-tools< 3.8.7-r2
Redhat3 products
Debian1 product
  • libarchive< 3.6.2-1+deb12u4 | < 3.7.4-4+deb13u1 | < 3.8.7-1
Libarchive1 product
Ubuntu1 product
  • libarchive< 3.1.2-7ubuntu2.8+esm5 | < 3.1.2-11ubuntu0.16.04.8+esm3 | < 3.2.2-3.1ubuntu0.7+esm3 | < 3.4.0-2ubuntu1.5+esm2 | < 3.6.0-1ubuntu1.7 | < 3.7.2-2ubuntu0.7 | < 3.7.7-0ubuntu3.2 | < 3.8.5-1ubuntu2.1

6 vendors · 14 products

References

9 links